Parts for your 1986 Mitsubishi Pajero-Throttle position sensors

1986 Mitsubishi Pajero throttle position sensor (TPS): what’s fitted and how it’s serviced

According to Mitsubishi’s factory literature for the first‑generation Pajero/Montero (Fuel – Group 13A for the Electronic Controlled Carburettor) and common aftermarket manuals covering 1983–1991 models, the 1986 petrol 2.6L 4G54 with the feedback Mikuni–Solex carburettor uses a throttle sensor/switch on the carburettor. Mitsubishi often calls it a “throttle sensor” or “idle/full‑throttle switch”. The Mitsubishi ASA/CAPS parts catalogue lists this sensor for the 4G54 carb variants, while mechanical‑injection diesels (4D55/4D56) are not shown with a TPS. So: on a 1986 Pajero, petrol feedback‑carb models use a TPS (switch‑type), many diesels do not. Market specs varied, but those sources make the TPS relevant for most 2.6 petrols of that year.

On the 1986 petrol Pajero with the feedback carb, the throttle position sensor’s job is to tell the engine control unit what the throttle is doing at idle and at wide‑open throttle, with some versions also providing a part‑throttle signal. The ECU uses that info to run the mixture control solenoids, tweak ignition timing, manage EGR, and keep drivability tidy under the bonnet. When the TPS goes out of whack, you’ll often cop a rough or high idle, flat spots on take‑off, poor fuel economy, or surging once it’s warm. There isn’t always a warning lamp on these early trucks, but a quick multimeter check against the workshop spec will usually dob it in.

Servicing is straightforward and suits a weekend spanner session. During regular tune‑ups (say every 20,000 km), it’s worth:

• Visually checking the TPS connector and loom for brittle insulation or green corrosion.
• Cleaning the plug with proper electrical contact cleaner, not WD‑40.
• Verifying switch operation with a multimeter per the factory service manual specs.

If replacement’s needed, disconnect the battery negative, unplug the sensor, mark its current position, then remove the two JIS screws on the carb bracket. Fit the new unit, lightly nip up the screws, and adjust the closed‑throttle switch using a feeler gauge or ohmmeter as specified in the manual, then tighten properly. A dab of anti‑seize on the screws isn’t a bad shout for future you. Because these are switch‑type rather than a modern potentiometer, they’re either spot‑on or not, adjustment often rescues them, but if the internals are worn, just replace. Always confirm base idle and mixture control after the job so the ECU can behave itself across town and out bush.

Technical references used: Mitsubishi Pajero/Montero Factory Service Manual (Fuel – Electronic Controlled Carburettor, circa mid‑1980s), Mitsubishi ASA/CAPS parts catalogue entries for L040 series (4G54 vs 4D55/4D56), and Haynes/Max Ellery manuals covering 1983–1991 Pajero/Montero.

FAQs

How can someone tell if their 1986 Pajero actually has a TPS?
On a petrol 2.6 with the feedback carb, look for a small black sensor mounted to the carburettor’s throttle shaft with a 2–3 wire plug. These vehicles also have an emissions control computer. Mechanical‑diesel models generally won’t have that sensor on the pump or throttle linkage.

Can the 1986 TPS be adjusted, or does it always need replacing?
It’s adjustable. It’s a switch‑type unit, so setting the idle and wide‑open switch points with a feeler gauge or multimeter per the factory spec is part of the job. If it won’t meet spec or behaves intermittently, replace it.

Where’s the TPS located on the 1986 petrol model?
Right on the side of the carburettor under the air cleaner, attached to the throttle shaft bracket. Pop the air cleaner lid and snorkel off for easier access under the bonnet.